mainlining shenanigans
29c2680fd2
With the last rework of the AP bus scan function one get_device() is
missing causing the reference counter to be one instance too
low. Together with binding/unbinding device drivers to an ap device it
may end up in an segfault because the ap device is freed but a device
driver still assumes it's pointer to the ap device is valid:
Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6803
Fault in home space mode while using kernel ASCE.
Krnl PSW : 0404e00180000000 000000001472f3b6 (klist_next+0x7e/0x180)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Call Trace:
[<000000001472f3b6>] klist_next+0x7e/0x180
([<000000001472f36a>] klist_next+0x32/0x180)
[<00000000147c14de>] bus_for_each_dev+0x66/0xb8
[<0000000014aab0d4>] ap_scan_adapter+0xcc/0x6c0
[<0000000014aab74a>] ap_scan_bus+0x82/0x140
[<0000000013f3b654>] process_one_work+0x27c/0x478
[<0000000013f3b8b6>] worker_thread+0x66/0x368
[<0000000013f44e32>] kthread+0x17a/0x1a0
[<0000000014af23e4>] ret_from_fork+0x24/0x2c
Kernel panic - not syncing: Fatal exception: panic_on_oops
Fixed by adjusting the reference count with get_device() on the right
place. Also now the device drivers don't need to adjust the ap
device's reference counting any more. This is now done in the ap bus
probe and remove functions.
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.